Three men, a woman and a teenage boy have been arrested on suspicion of terrorism offences.
Officers from Counter Terrorism Policing North East arrested a 29-year-old man, a 30-year-old man and a 28-year-old woman in Keighley, West Yorkshire, on Saturday morning on suspicion of being concerned in the commission, preparation or instigation of acts of terrorism under Section 41 of the Terrorism Act 2000.
A 28-year-old man was arrested in Anglesey, north Wales, and a 16-year-old boy was arrested in Swindon, Wiltshire, on Saturday morning on suspicion of the same offence.
All five have been taken to a police station in West Yorkshire for questioning, Counter Terrorism Policing North East said.
A number of properties are currently being searched in connection with the arrests which form part of an ongoing investigation into right-wing terrorism.
West Yorkshire Police said the Explosive Ordnance Disposal Unit (EOD) had been called to offer advice on “potentially suspicious material” found at an address in Keighley.
A police statement said: “Two addresses in Keighley are currently being searched in connection with this investigation.
“Following the discovery of potentially suspicious material at one of the addresses in Keighley the Explosive Ordnance Disposal Unit (EOD) has been called to provide specialist advice and to arrange the safe removal of the items if required.
“As a precautionary measure, a cordon has been put in place and a number of local residents have evacuated whilst examinations are conducted.”
The Counter Terrorism Policing North East statement added: “We recognise that local people may have concerns as a result of this activity.
“We would like to reassure them that these arrests are pre-planned and intelligence-led and there is not believed to be any immediate risk to the local community.
“We are grateful for the understanding, patience and support of local residents while these inquiries continue.”